With a rapid development of the wind power technology, wind farms in various environments are developed. Failures may be occurred in a wind turbine generator system (referred to as “wind turbine” for short) under a bad weather condition such as frosty and wind. In particular to a wind direction sensor of the wind turbine, extreme weather or prolonged operation will cause the wind direction sensor to fail.
Once the wind direction sensor fails, those skilled in the art are required to repair or replace the wind direction sensor in a better weather condition. Before the wind direction sensor is repaired or replaced, the wind turbine may not yaw to align wind to obtain the maximum wind power, even the wind turbine stops operating, thereby extremely affecting a utilization rate and a power-generating capacity of the wind turbine.